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Building new WSL2 Linux Kernel 6.6 disables /dev/dri (and VA-API) #11837

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Description

@sikhness

Windows Version

Microsoft Windows [Version 10.0.20348.2582] (Windows Server 2022)

WSL Version

2.2.4.0

Are you using WSL 1 or WSL 2?

  • WSL 2
  • WSL 1

Kernel Version

6.6.36.3-microsoft-standard-WSL2

Distro Version

Ubuntu 24.04

Other Software

No response

Repro Steps

  1. Build the new WSL2 Linux 6.6.36.3 kernel release
  2. Spin up a Ubuntu 24.04 (or even Ubuntu 22.04) WSL2 instance
  3. Observe that /dev/dri is not there

Expected Behavior

/dev/dri should be present just like before using the older kernel

Actual Behavior

/dev/dri is missing and this makes VA-API impossible.

Workaround

I think the issue seems to be around the way the kernel config is set up. After much debugging, I found that /dev/dri is mapped using VGEM as described in this commit. I then noticed that in the config for the kernel, CONFIG_DRM_VGEM=m instead of CONFIG_DRM_VGEM=y like in the older WSL2 kernels. After changing the m to y for CONFIG_DRM_VGEM and rebuilding the WSL2 kernel, /dev/dri seems to show up again.

This should probably be fixed directly in the config.

Diagnostic Logs

No response

Activity

  1. github-actions commented on Jul 25, 2024

    @github-actions
    Contributor

    Logs are required for review from WSL team

    If this a feature request, please reply with '/feature'. If this is a question, reply with '/question'.
    Otherwise please attach logs by following the instructions below, your issue will not be reviewed unless they are added. These logs will help us understand what is going on in your machine.

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    Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/WSL/master/diagnostics/collect-wsl-logs.ps1" -OutFile collect-wsl-logs.ps1
    Set-ExecutionPolicy Bypass -Scope Process -Force
    .\collect-wsl-logs.ps1
    

    The script will output the path of the log file once done.

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  2. sikhness commented on Jul 25, 2024

    @sikhness
    Author

    /feature

    I'm tagging this as a feature request since I have provided the solution in the workaround. No logs are really needed as this one involves building the kernel and following the steps to reproduce the issue.

  3. github-actions commented on Jul 25, 2024

    @github-actions
    Contributor
    Diagnostic information
    Found '/feature', adding tag 'feature'
    
  4. zcobol commented on Jul 26, 2024

    @zcobol

    From https://github.com/microsoft/WSL2-Linux-Kernel/releases

    We are very excited kernel module support is now available in WSL2! With this latest kernel update, a large set of loadable modules has been introduced, accompanied by an overall config file update. However, please be aware that when using a custom kernel, the default module support is disabled for now. If you’re using a custom kernel, we recommend you edit your kernel config file to build-in all of the modules that you need.

  5. sikhness commented on Jul 26, 2024

    @sikhness
    Author

    Thanks Toto (@zcobol), I did read that as part of the release notes, but since this is to be the new LTS kernel and the default one at some point soon when you update WSL, I'd imagine that feature (CONFIG_DRM_VGEM) should be enabled by default. Perhaps it is planned to be done, but I just wanted to open an issue regarding that in case it was not (especially since VA-API is a supported and default feature set for WSL).

  6. benhillis commented on Jul 26, 2024

    @benhillis
    Member

    The kernel module is included, can you simply load the module (sudo modprobe vgem)?

  7. sikhness commented on Jul 29, 2024

    @sikhness
    Author

    Ben Hillis (@benhillis), I haven't tried loading it explicitly, but I raised this issue hoping that in the WSL2 kernel code, perhaps it's a good idea to have it enabled by default so that manual commands don't need to be run each time WSL2 is started to load the VGEM module. It should in theory work out-of-the-box as it does in the older 5.15 kernel.

  8. Ryderjj89 commented on Aug 1, 2024

    @Ryderjj89

    Just updated WSL to 2.3.13 and also noticed that /dev/dri was missing. This is required for Emby Media Server to run. Using the sudo modprobe vgem worked, but if this is something that has to be done every time the server restarts, then it really should be enabled by default.

  9. Molyleaf commented on Oct 18, 2025

    @Molyleaf

    sudo modprobe vgem successfully solved my problem

  10. LiamKarlMitchell commented on Oct 24, 2025

    @LiamKarlMitchell

    sudo modprobe vgem does not use real gpu on host however right?

  11. gbShaw commented on Mar 24, 2026

    @gbShaw

    sudo modprobe vgem 成功解决了我的问题

    that works. Great!

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